Semaphore.h

//// Semaphore.h//// $Id: //poco/1.3/Foundation/include/Poco/Semaphore.h#2 $//// Library: Foundation// Package: Threading// Module: Semaphore//// Definition of the Semaphore class.//// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.// and Contributors.//// Permission is hereby granted, free of charge, to any person or organization// obtaining a copy of the software and accompanying documentation covered by// this license (the "Software") to use, reproduce, display, distribute,// execute, and transmit the Software, and to prepare derivative works of the// Software, and to permit third-parties to whom the Software is furnished to// do so, all subject to the following:// // The copyright notices in the Software and this entire statement, including// the above license grant, this restriction and the following disclaimer,// must be included in all copies of the Software, in whole or in part, and// all derivative works of the Software, unless such copies or derivative// works are solely in the form of machine-executable object code generated by// a source language processor.// // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER// DEALINGS IN THE SOFTWARE.//#ifndef Foundation_Semaphore_INCLUDED#define Foundation_Semaphore_INCLUDED#include "Poco/Foundation.h"#include "Poco/Exception.h"#if defined(POCO_OS_FAMILY_WINDOWS)#include "Poco/Semaphore_WIN32.h"#else#include "Poco/Semaphore_POSIX.h"#endifnamespace Poco {
00057class Foundation_API Semaphore: private SemaphoreImpl /// A Semaphore is a synchronization object with the following /// characteristics: /// A semaphore has a value that is constrained to be a non-negative /// integer and two atomic operations. The allowable operations are V /// (here called set()) and P (here called wait()). A V (set()) operation /// increases the value of the semaphore by one. /// A P (wait()) operation decreases the value of the semaphore by one, /// provided that can be done without violating the constraint that the /// value be non-negative. A P (wait()) operation that is initiated when /// the value of the semaphore is 0 suspends the calling thread. /// The calling thread may continue when the value becomes positive again.{
public:
Semaphore(int n);
Semaphore(int n, int max); /// Creates the semaphore. The current value /// of the semaphore is given in n. The /// maximum value of the semaphore is given /// in max. /// If only n is given, it must be greater than /// zero. /// If both n and max are given, max must be /// greater than zero, n must be greater than /// or equal to zero and less than or equal /// to max.
~Semaphore(); /// Destroys the semaphore.voidset(); /// Increments the semaphore's value by one and /// thus signals the semaphore. Another thread /// waiting for the semaphore will be able /// to continue.void wait(); /// Waits for the semaphore to become signalled. /// To become signalled, a semaphore's value must /// be greater than zero. /// Decrements the semaphore's value by one.void wait(long milliseconds); /// Waits for the semaphore to become signalled. /// To become signalled, a semaphore's value must /// be greater than zero. /// Throws a TimeoutException if the semaphore /// does not become signalled within the specified /// time interval. /// Decrements the semaphore's value by one /// if successful.bool tryWait(long milliseconds); /// Waits for the semaphore to become signalled. /// To become signalled, a semaphore's value must /// be greater than zero. /// Returns true if the semaphore /// became signalled within the specified /// time interval, false otherwise. /// Decrements the semaphore's value by one /// if successful.private:
Semaphore();
Semaphore(constSemaphore&);
Semaphore& operator = (constSemaphore&);
};
//// inlines//00129inlinevoidSemaphore::set()
{
setImpl();
}
00135inlinevoid Semaphore::wait()
{
waitImpl();
}
00141inlinevoidSemaphore::wait(long milliseconds)
{
if (!waitImpl(milliseconds))
throw TimeoutException();
}
00148inlineboolSemaphore::tryWait(long milliseconds)
{
return waitImpl(milliseconds);
}
} // namespace Poco#endif // Foundation_Semaphore_INCLUDED